汶川特大地震后成都盆地内隐伏断层活动性分析

成都盆地内主要有3条隐伏的活动断裂带,包括大邑断裂带、蒲江-新津断裂带和龙泉山断裂带,它们在第四纪都表现出了一定的活动性."512"汶川特大地震后,笔者实地考察的结果表明,在汶川特大地震中成都盆地中的隐伏断裂没有产生新的活动性,目前成都盆地不存在发生特大地震的危险性,是安全的.     

塔里木盆地塔河地区下石炭统巴楚组沉积演化

以塔里木盆地加里东期和海西两期构造运动为背景,结合现有的岩心、露头、测井、录井和地震资料,对巴楚组可识别出早期的辫状河三角洲沉积,中期的渴湖沉积和盐湖沉积,以及晚期的咸化溻湖沉积。本文分别从横向上和纵向上对塔河地区巴楚组沉积演化进行深入分析;总结了巴楚组构造运动与沉积响应之间的关系,以期为该地区的下石炭统巴楚组的进一步勘探提供科学依据。     

准噶尔盆地西北缘走滑断层特征及油气地质意义

准噶尔盆地西北缘前陆冲断带构造样式复杂多样,除规模较大的逆断层外,还发育一系列北西向的走滑断层。以高分辨率三维地震资料为基础,对断裂体系分析表明克拉玛依—百口泉地区的走滑断层可分为花状走滑断层和简单走滑断层两类,二者在成因、剖面特征等方面具有明显差别。研究结果认为走滑断层对油气的运聚成藏具有重要的双重控制作用,即能作为有效的运移通道,又能够起遮挡作用而形成圈闭。     

准噶尔盆地西北缘三叠系层序地层与隐蔽油气藏勘探

层序地层学及层序地层原理指导下的地震资料解释为地层、岩性油气藏勘探提供了理论和技术支持。为配合准噶尔盆地西北缘油气勘探从克乌断裂带上盘向下盘、从构造油气藏向地层、岩性等隐蔽油气藏的转变,利用陆相层序地层学理论和地球物理资料,将三叠系划分为1个二级层序、5个三级层序和8个体系域,进而总结出拗陷完整型和拗陷残缺型两种层序类型。结合测井约束地震反演和井间沉积对比,探讨了三叠系砂体结构和湖侵体系域地层超覆、湖退体系域及最大湖泛面附近小规模滑塌浊积体岩性透镜体等5种圈闭发育模式。油气成藏综合条件分析指出有效圈闭和油源断层的识别是制约斜坡带岩性油气藏勘探的关键。     

准噶尔盆地中部III 区块原油中25-降藿烷分布特征与成因意义

通过对准噶尔盆地中部Ш区块原油或油砂抽提物的饱和烃气相色谱-质谱分析,研究了原油或油砂抽提物中25-降藿烷的分布规律.结果表明,不同井区或同一口井不同深度(层位)的原油25-降藿烷的相对含量存在比较明显的差别,表明其所遭受的生物降解程度有所差异,沿构造带从南到北,同一油层中原油的生物降解程度增强,比如位于构造北部(构造部位相对较高)的永1井、永3井侏罗系原油25-降藿烷丰度较高,表明生物降解比较明显,而位于南部(构造低部位)的永6井白垩系和侏罗系油层中的原油均无明显的生物降解现象;同一口井随深度增大生物降解作用将弱,如永2井浅部白垩系油层的原油降解较严重,而深部西山窑组的原油降解作用则不明显.根据原油生物降解的特征,结合车-莫古隆起调整对研究区油气成藏的影响,讨论了原油生物降解差异分布的成因机制.     

柴达木盆地西南部砂6井第三系沉积相研究

结合前人的研究成果,运用野外地质剖面、测井相标志的研究方法,对柴达木盆地西南第三系沉积相进行了较全面、系统的研究,描述了柴达木盆地砂6井第三系主要发育的三种沉积相及发育的主要类型,指出了研究区内有利于油气生成和储集的沉积相类型。     

New basin modelling results from the Polish part of the Central European Basin system: implications for the Late Cretaceous–Early Paleogene structural inversion

Combined subsidence and thermal 1D modelling was performed on six well-sections located in the north-western Mid-Polish Trough/Swell in the eastern part of the Central European Basin system. The modelling allowed constraining quantitatively both the Mesozoic subsidence and the magnitude of the Late Cretaceous–Paleocene inversion and erosion. The latter most probably reached 2,400 m in the Mid-Polish Swell area. The modelled Upper Cretaceous thickness did not exceed 500 m, and probably corresponded to 200–300 m in the swell area as compared with more than 2,000 m in the adjacent non-inverted part of the basin. Such Upper Cretaceous thickness pattern implies early onset of inversion processes, probably in the Late Turonian or Coniacian. Our modelling, coupled with previous results of stratigraphic and seismic studies, demonstrates that the relatively low sedimentation rates in the inverted part of the basin during the Late Cretaceous were the net result of several discrete pulses of non-deposition and/or erosion that were progressively more pronounced towards the trough axis. The last phase of inversion started in the Late Maastrichtian and was responsible for the total amount of erosion, which removed also the reduced Upper Cretaceous deposits. According to our modelling results, a Late Cretaceous heat-flow regime which is similar to the present-day conditions (about 50 mW/m²) was responsible for the observed organic maturity of the Permian-Mesozoic rocks. This conclusion does not affect the possibility of Late Carboniferous–Permian and Late Permian–Early Triassic thermal events.     

Strain localization due to structural in-homogeneities in the Central European Basin System

The large-scale crustal deformations observed in the Central European Basin System (CEBS) are the result of the interplay between several controlling factors, among which lateral rheological heterogeneities play a key role. We present a finite-element integral thin sheet model of stress and strain distribution within the CEBS. Unlike many previous models, this study is based on thermo-mechanical data to quantify the impact of lateral contrasts on the tectonic deformation. Elasto-plastic material behaviour is used for both the mantle and the crust, and the effects of the sedimentary fill are also investigated. The consistency of model results is ensured through comparisons with observed data. The results resemble the present-day dynamics and kinematics when: (1) a weak granite-like lower crust below the Elbe Fault System is modelled in contrast to a stronger lower crust in the area extending north of the Elbe Line throughout the Baltic region; and (2) a transition domain in the upper mantle is considered between the shallow mantle of the Variscan domain and the deep mantle beneath the East European Craton (EEC), extending from the Elbe Line in the south till the Tornquist Zone. The strain localizations observed along these structural contrasts strongly enhance the dominant role played by large structural domains in stiffening the propagation of tectonic deformation and in controlling the basin formation and the evolution in the CEBS.     

High-resolution seismic analysis of the coastal Mecklenburg Bay (North German Basin): the pre-Alpine evolution

The pre-Alpine structural and geological evolution in the northern part of the North German Basin have been revealed on the basis of a very dense reflection seismic profile grid. The study area is situated in the coastal Mecklenburg Bay (Germany), part of the southwestern Baltic Sea. From the central part of the North German Basin to the northern basin margin in the Grimmen High area a series of high-resolution maps show the evolution from the base Zechstein to the Lower Jurassic. We present a map of basement faults affecting the pre-Zechstein. The pre-Alpine structural evolution of the region has been determined from digital mapping of post-Permian key horizons traced on the processed seismic time sections. The geological evolution of the North German Basin can be separated into four distinct periods in the Rerik study area. During Late Permian and Early Triassic evaporites and clastics were deposited. Salt movement was initiated after the deposition of the Middle Triassic Muschelkalk. Salt pillows, which were previously unmapped in the study area, are responsible for the creation of smaller subsidence centers and angular unconformities in the Late Triassic Keuper, especially in the vicinity of the fault-bounded Grimmen High. In this area, partly Lower Jurassic sediments overlie the Keuper unconformably. The change from extension to compression in the regional stress field remobilized the salt, leading to a major unconformity marked at the base of the Late Cretaceous.